Datasheet

AD9772A
Rev. C | Page 8 of 40
DIGITAL FILTER SPECIFICATIONS
T
MIN
to T
MAX
, AVDD = 3.3 V, CLKVDD = 3.3 V, PLLVDD = 0 V, DVDD = 3.3 V, I
OUTFS
= 20 mA, differential transformer-coupled output,
50 Ω doubly terminated, unless otherwise noted.
Table 4.
Parameter Min Typ Max Unit
MAXIMUM INPUT DATA RATE (f
DATA
) 150 MSPS
DIGITAL FILTER CHARACTERISTICS
Pass-Bandwidth
1
: 0.005 dB 0.401 f
OUT
/f
DATA
Pass-Bandwidth: 0.01 dB 0.404 f
OUT
/f
DATA
Pass-Bandwidth: 0.1 dB 0.422 f
OUT
/f
DATA
Pass-Bandwidth: −3 dB 0.479 f
OUT
/f
DATA
LINEAR PHASE (FIR IMPLEMENTATION)
STOP BAND REJECTION 73 dB
0.606 f
CLOCK
to 1.394 f
CLOCK
11 Input clocks
GROUP DELAY
2
IMPULSE RESPONSE DURATION
−40 dB 36 Input clocks
−60 dB 42 Input clocks
1
Excludes sin(x)/x characteristic of DAC.
2
Defined as the number of data clock cycles between impulse input and peak of output response.
FREQUENCY (DC TO f
DATA
)
0
–140
0
1.00. 1
OUTPUT (dB)
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
–20
–40
–60
–80
–100
–120
0
2253-004
Figure 4. FIR Filter Frequency Response—Baseband Mode
TIME (Samples)
1.0
–0.4
0
5
NORMALIZED OUTPUT
10 15 20 25 30 35 40 45
0.8
0.6
0.4
0.2
0
–0.2
02253-005
Figure 5. FIR Filter Impulse Response—Baseband Mode
Table 5. Integer Filter Coefficients for Interpolation Filter
(43-Tap Half-Band FIR Filter)
Lower
Coefficient
Upper
Coefficient
Integer
Value
H(1) H(43) 10
H(2) H(42) 0
H(3) H(41) −31
H(4) H(40) 0
H(5) H(39) 69
H(6) H(38) 0
H(7) H(37) −138
H(8) H(36) 0
H(9) H(35) 248
H(10) H(34) 0
H(11) H(33) −419
H(12) H(32) 0
H(13) H(31) 678
H(14) H(30) 0
H(15) H(29) −1083
H(16) H(28) 0
H(17) H(27) 1776
H(18) H(26) 0
H(19) H(25) −3282
H(20) H(24) 0
H(21) H(23) 10,364
H(22) 16,384